Livt.Utils

tests/hashing/CrcTest.lvt

namespace Livt.Utils.Tests.Hashing

using Livt.Utils.Hashing

/**
 * Published check values exercise small/large widths and both bit directions.
 */
@Test
component CrcTest
{
	// Independent compile-time profiles; helpers own no running state.
	crc5: Crc<5, 0x05, true>
	crc16: Crc<16, 0x8005, true>
	crc32: Crc
	ccitt: Crc<16, 0x1021, false>
	parity: Crc<1, 1, true>
	forwardParity: Crc<1, 1, false>

	/**
	 * Constructs the profile specializations.
	 */
	new()
	{
		crc5 = new Crc<5, 0x05, true>()
		crc16 = new Crc<16, 0x8005, true>()
		crc32 = new Crc()
		ccitt = new Crc<16, 0x1021, false>()
		parity = new Crc<1, 1, true>()
		forwardParity = new Crc<1, 1, false>()
	}

	/**
	 * Check strings use independent CRC-5/USB, CRC-16/USB, CRC-32/ISO-HDLC and
	 * CRC-16/IBM-3740 vectors; the latter exercises non-reflected operation.
	 */
	@Test
	fn CheckProfiles()
	{
		var input: byte[9] = [0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39]
		var five: logic[5] = 0x1F
		var sixteen: logic[16] = 0xFFFF
		var thirtyTwo: logic[32] = 0xFFFFFFFF
		var forward: logic[16] = 0xFFFF

		for (var index = 0; index < 9; index++) {
			five = crc5.UpdateByte(five, input[index])
			sixteen = crc16.UpdateByte(sixteen, input[index])
			thirtyTwo = crc32.UpdateByte(thirtyTwo, input[index])
			forward = ccitt.UpdateByte(forward, input[index])
		}

		assert crc5.Finalize(five, 0x1F, false) == 0x19
		assert crc16.Finalize(sixteen, 0xFFFF, false) == 0xB4C8
		assert crc32.Finalize(thirtyTwo, 0xFFFFFFFF, false) == 0xCBF43926
		assert forward == 0x29B1
		assert ccitt.Finalize(forward, 0, true) == 0x8D94
	}

	/**
	 * A token covers eleven bits, not two padded bytes. Empty data CRC is zero.
	 */
	@Test
	fn CheckBitUpdatesAndEmpty()
	{
		var token: logic[5] = 0x1F

		for (var index = 0; index < 11; index++) {
			token = crc5.UpdateBit(token, false)
		}

		assert crc5.Finalize(token, 0x1F, false) == 0x02
		assert crc16.Finalize(0xFFFF, 0xFFFF, false) == 0
		assert parity.UpdateByte(0, 0x01) == 1
		assert forwardParity.UpdateByte(0, 0x03) == 0
	}
}